Successive Promotion, Gradual Promotion, Graduated
noun, verbal noun
Accumulate enough of a good reputation at your company in advance and you'll be able to have successive promotions. You'll be boss in no time!
るいしん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
彼は若くして部長に累進した。
He was promoted to section head at a very young age.